1. Field of the Invention
This invention relates generally to plant pots, and more particularly to self-watering plant pots.
2. Description of the Prior Art
Potted plants must be watered regularly if they are to survive and grow. Unfortunately, many people neglect to properly water their plants.
Due to this problem, a number of prior art plant pots are designed to automatically water the plants which they contain. For example, U.S. Pat. No. 2,950,567 of Newman teaches a plant pot placed within a closed terrarium where water vapor condenses along the top and sides of the terrarium and is directed back to the pot by a number of conduits.
In U.S. Pat. No. 4,125,963 of Johnson, a self-watering plant box is disclosed including a semi-spherical bowl for containing dirt, and a conical tower attached over the bowl which has a water reservoir and a number of condensation plates. Water vapor from the reservoir condenses on the condensation plates and drips into the dirt below
In U.S. Pat. No. 4,178,715 of Greenbaum an irrigation assembly includes an array of V-shaped, soil containing channels in a side-by-side relationship. The array is placed on a base over which a contaminated water, such as seawater, flows. Water vapor from the seawater permeates through apertures provided in the channels to moisten the soil within the V-shaped channels. The portion of the array in contact with the seawater is liquid impermeable, and zones beneath the V-shaped channels where water vapor is present is vented to the atmosphere through apertures in end plates of the array. Due to the venting of the zones beneath the V-shaped channels, there is not a pressure differential between the zones and the interior of the channels As a result, air is not forced into the interior of the V-shaped channels to aerate the soil. Furthermore, because of the lack of a pressure differential, water vapor is not efficiently forced into the soil.
In U.S. Pat. Nos. 4,133,141 of Lee and No. 4,173,098 of Smith, self-watering plant pots are disclosed in which a barrier separates a section filled with dirt from a section filled with water. Other examples of self-watering plant pots can be found in U.S. Pat. No. 4,083,147 of Garrick, No. 4,001,967 of Swift et al., No. 2,807,912 of Bjorksten, and No. 4,315,599 of Biancardi.
As mentioned previously, the prior art does not address the problem of root aeration. If a plant is over-watered, air pockets within the soil are saturated which deprives the plant roots of oxygen. With self-watering plant pots which continuously recycle water, root asphyxiation becomes a major problem.
A drawback of many prior art self-watering plant pots is that they are not closed systems. Thus, in devices such as those disclosed in Johnson and Smith, the plant pots must frequently be refilled with water.
A drawback of prior art self-watering plant pots which operate on an evaporation/condensation cycle is that they can only operate efficiently when the ambient temperature is high enough to vaporize large quantities of water. Many such plant waterers therefore do not provide sufficient water to keep the plants alive during extended cool or cold periods